Skewback structural shape for furnace structures



Sept 14, 19 4 w. POTTMEYER SKEWBACK STRUCTURAL SHAPE FOR FURNACESTRUCTURES 2 Sheets-Sheet 1 Filed Oct. 19 1950 I NVE NTOR Edward/)[Efhm0 a 1 in Z Z f l I ll Ill Sept. 14, 1954 E. w. POTTMEYER SKEWBACKSTRUCTURAL SHAPE FOR FURNACE STRUCTURES 2 Sheets-Sheet 2 Filed Oct. 19,1950 3%; R n 3 0 m n 00 mww 8 m a 4 34 I 1 EMMA Patented Sept. 14, 1954SKEWBACK STRUCTURAL SHAPE FOR FURNACE STRUCTURES Edward W. Pottmeyer,Pittsburgh, Pa., assignor,

by mesne assignments, to Blew-Knox Company, Pittsburgh, Pa., acorporation of Dela- Ware Application October 19, 1950, Serial No.190,979

4 Claims. l

This invention relates to an elongated skewback structural shapepreferably made of ferrous metal for use in oven-hearth furnaces or thelike. More particularly, it relates to such a structural shape in thegeneral form of a skewback member having a markedly increased sectionmodulus about its vertical neutral axis, while at the same timeproviding cooling passages for the flanges thereof. In addition, the newskewback structural shape of this invention is reversible whereby thelife thereof may be markedly extended.

In furnace structures such as an open-hearth furnace, the frameworkthereof is made of steel. In order to protect such framework fromexposure to the high temperatures inside the furnace, in those furnacestructures in which the refractory roof is arched from front to back butnot from side to side, structural steel skewback channels are employedas an element of the framework across the back and front of the furnaceto support the weight and thrust of the arched roof. deterioration ofthe protective refractory of the roof, may expose a certain portion ofthe metal thereof to the flame and temperatures inside the furnace. Itis necessary in most industrial furnaces to replace such doorframes andto either replace or reline the doors with refractory during the life ofthe furnace. This can generally be conveniently accomplished at anytime. But

Such skewback channels, due tobecause of the foundation nature of theskewback channels, the replacement thereof can be undertaken only aftera portion of the roof of the furnace has been torn down for rebuilding.Such rebuilding may occur two or more times during a furnace campaign.

In such furnace structures the skewback channel across the framework atthe front of the furnace may be bolted to the adjacent verticalbuckstays; or alternatively, the skewback channel may be suspended onrods hanging from the furnace framework binding and bear against thebuckstays without any rigid connection thereto. The conventionalskewback channel is protected against the heat of the furnace by askewback brick and the top of the refractory arch constructed across thetop of the charging openings. In those furnaces employing an archlesstype of doorframe, a water-cooled ledge may be provided in the doorframewhich extends under the lower flange of this conventional skewbackchannel to keep it from burning away in the course of operation. Inalmost all of such cases, the tops of the doorframe used in such furnacestructures rest against or are connected to the skewback channel when inposition around its respective furnace opening. These doorframes arereadily removable by sliding them up past the front of the skewbackchannel as a rule inasmuch as they are usually replaced during the lifeof the furnace structure. At the same time, such doorframes should fitrelatively close to make the furnace structure as tight as possible, yetwith conventional skewback channels the outside of the web facing thedoorframe has in many cases been known to bulge outwardly making itimpossible to make a proper fit between the skewback channel and thedoorframe. In fact, in extreme cases, such; bulging might result infailure of the roof with consequent hazard and loss of production.

In the novel skewback structural shape of this invention, any suchbulging or tendency to bulge is prevented. Further, this new structuralshape is reversible so that as and when the furnace is rebuilt, therespective bottom and top of the new shape can be reversed, greatlylengthening the useful life thereof. I-Ieretofore, when the lower partof the skewback channels deteriorated to a certain point under thesevere conditions of their use, they have been discarded in many casesbefore the remainder of the furnace framework required any replacement.In addition, in the skewback structural shape of this invention, thesame elements thereof that enable it to achieve marked superiority inresistance to horis zontal bending thrust also enable it to be cooled.

Thus, even if it be used with an archless type of doorframe, nowater-cooled ledge will be required therein.

Other objects and advantages will be apparent from the followingdescription and from the following drawings, which are illustrativeonly, in which,

Figure 1 is a front view of a charging door section for an open-hearthfurnace employing the new skewback structural shape of this invention;

Figure 2 is a view of the assemblage shown in Figure 1 taken from insidethe furnace;

Figure 3 is a view in section of a portion of the assemblage shown inFigure 1 taken along line IIIIII thereof;

Figure 4 is a view in elevation of the front of a skewback structuralshape embodying the teachings of this invention;

Figure 5 is a view in elevation of the back of the structural shapeshown inFigure 4;

Figure 6 is an end view in elevation of the structural shape shown inFigure 4;

Figure 7 is a view in section of the structural shape shown in Figure 4taken along line VII-VII thereof; and

Figure 8 is a view in section similar to Figure '7 of a modified form ofthe structural shape of this invention.

Referring to the drawings, a set of buckstays l forming a part of theframework of an openhearth furnace extend vertically on each side of acharging opening H extending through the front wall of the furnace. Thisopening is defined horizontally by the distance between the legs of adoorframe I2 and defined vertically by the distance between the bottomedge of the top 13 of said doorframe l2 and the top of a foreplate l4.Foreplate I4 is supported on a breast plate It also forming a part ofthe aforesaid framework between the buckstays it. The front or outsideof doorframe i2 is provided with integral door guides I6 thereon betweenwhich a charging door II is adapted to slide. Rods i8 pivotallyconnected to the lugs at the top of door II are also connected toelevating mechanism for operating the door to open and close the openingH as required. In its closed position, as shown in Figures 1 and 2, thebottom of the door ll, which as shown is of a panel type, rests uponforeplate M. Similarly, when frame I2 is to be removed or replaced, theeyes l9 welded to the top thereof are engaged by lifting mechanism sothat the doorframe can be removed. In its operative position, as shownin Figures 1 and 2, the frame may be conveniently bolted to the sides ofthe respective buckstays.

As shown in Figure 3, the top 13 of doorframe l2 rests in snug closefitting engagement against the smooth front side of the skewbackstructural shape 2&9 which structural shape embodies the teaching ofthis invention. In this way, a close relatively tight fit exists betweenthe members 26 and the doorframe if. The inside of the rest of thedoorframe similarly fits between the buckstays [0 against the refractorywalls M on the inside of the furnace above the hearth The skewbackstructural shape so may be provided with drilled openings 23 in the web22 thereof against the front of which top l3 rests. Bolts 25 extendthrough registering openings in the clip angles its. welded to buckstaysit and the drilled openings 23 so that the skewback member 2% may befirmly attached to the furnace framework by the tightening of the nuts26. Alternatively, vertical hanger rods which are not illustrated may besuspended from the upper part of the furnace framework and attached tothe skewback member 20 to support the load imposed thereupon by arefractory roof 2i. A skewback refractory shape 28 is interposed betweenthe member 28 and the edge of the arching roof 2'5.

The front of web 24 presents, between the buckstays, a smooth planarsurface against which the inside of the top l3 of doorframe 52 can restand the doorframe itself slide during the installation and removalthereof from the furnace. On opposite side, the roof 2'? transmits agenerally horizontal relatively tremendous thrust against the inside orback of web 2d as shown in Figure 3 tending to bulge it in the directionof the frame I2. Such bulges Whichoccurred with prior skewback channelsmight impair both the fit of the doorframe and the economy of thefurnace.

In this invention, the new structural shape 20 is provided, havinga'section modulus about ably made out of the same plate from which the.

web 24 is formed. Thus, each flange comprises a side 30 forming aright-angle bend with the web 2% and extending inwardly and normalthereto. A second side 3| of each flange 29 is a further right-anglebend from side 30 extending parallel to the web 24 and away from thehorizontal center line thereof. A third side 32 of the flange 29 forms afurther right-angle bend from side 3| but extends toward the web 26 andnormal thereto. The fourth side 33 of the respective flanges 29 forms astill further right-angle bend continuation of side 32 but side 33 is inthe plane of and extends toward the horizontal center line of web 2d.The edge of side 33 is continuously welded to web 2d at the firstright-angle bend between the said web and the side 35% Each such flange29 thus is a box section of a hollow rectangular nature completelysealed along the length of the member 20. Moreover, the side 33 is ineffect a vertical continuation of the web 24 and the weld material 34between the edges of the sides 33 is made flush with the outside of web2% so that the smooth planar surface thereof is unimpaired.

The flanges 29 are parallel to and equidistant from the horizontalcenter line of the structural shape 2d making the skewback 2dsymmetrical about its horizontal center line. It is also symmetricalabout its vertical center line. Each of the hollow flanges 29 is closedat its ends by the respective plates 35 welded around the edges thereofto the inside of flange 29. Preferably, the closure plates 35 are flushwith the ends of the skewback 20 but they may be placed somewhatinwardly of the ends of the flanges 29. Female nipples in the form ofpipe connections 35 are rigidly connected to the outside or front of thesides 33 of the flanges 29. Each pair of connections 3% adjacent therespective ends of each flange 29 communicate with the interior thereofthrough an opening 37 in registry with the openings in the connections35.

As a general rule only the lower flange of a skewback member requiresprotection against being burned away in the course of use in a furnacestructure such as an open-hearth furnace. By means of the provision ofthis invention, whichever of the flanges 29 is the lower can be itselfdirectly cooled by rigging inlet and outlet water hose connectionsrespectively (not illustrated) to the pair of pipe connections 36communicating with the interior of whichever of the said flanges 29 isthe lower. These hose connections as shown in Figures 1 and 2 are sopositioned along the skewback member 20 as to lie to the respectivesides of the doorframe I2. Hence, they do not interfere with the normaloperation in the installation and removal of such frames. Moreover, asand when the roof of a furnace in which a structural shape 26 may beemployed, is rebuilt, the top and bottom of the skewback channel can bereversed whenever the condition of the flange 29, which has been in thelower position, renders such a reversal desirable. In such a case, thelower flange 29 becomes the upper flange and vice versa. By such means,it is evident that the skewback shape of this invention provides amember which not only has a section modulus about its generally verticalneutral axis of such a kind as to prevent lateral or transverse bulgingunder the horizontal thrust of roof 21, but it also provides astructural shape which is capable of a greatly extended life as a partof' the framework of the particular furnace to which it is applied.

A modified embodiment of this invention is shown in cross section inFigure 8. In that figure a structural shape 44 is similar in generalconstruction and purpose to member 20 except that in the modification,the flanges 38 are differently formed. Thus, each flange 38 involves butthree right-angle bends respectively forming the sides 39, 49 and 4|.The edge of side 4! is welded at 42 to the inside or back of the web 43.Various other modifications in the size and dimensions of the structuralshape of this invention and of the means for fastening such to theframework of the furnace structures to which applied may be made withoutdeparting from, the spirit of this invention as defined by the scope ofthe appended claims.

I claim:

1. An elongated reversible structural support for a skewback in anopen-hearth furnace or the like, comprising, in combination, a generallyvertical web adapted to bear at spaced horizontal intervals against theframework of such furnace or the like, hollow box section flangesextending along the horizontal edges of said web in symmetrical andrigid relation thereto, the section modulus of said support beingsufiicient to resist the thrust of the skewback without material outwardbulging, and closures for the respective ends of said flanges to formcooling passages therethrough and provide coolable flanges.

2. An elongated structural support for a skewback in an open-hearthfurnace or the like, comprising, in combination, a vertical web havingits back engage the buckstays and framework at spaced horizontalintervals, generally tubular flanges formed integrally along thehorizontal edges of said web equidistant from the horizontal center linethereof, a plate sealing oiT the open ends of each of said'flanges insubstantially flush relation with the ends of said support, said flangeshaving fluid circulation openings into the interior thereof intermediatetheir ends, whereby the bottom of said support may be placed inhorizontal top position after a predetermined period of use and thatflange on the bottom at the time being may be used as a cooling passage.

3. An elongated structural support member for a skewback in anopen-hearth furnace or the like,

comprising, in combination, a vertical web bearing at spaced horizontalintervals against vertical framework members of said furnace or thelike, box section flanges formed integrally along the horizontal top andbottom edges respectively of said support member, each of said flangesbeing formed from the same plate material forming said web, said flangecomprising a right-angle bend inwardly of said web and normal thereto, afurther right-angle bend parallel to said web extending away from thehorizontal center line thereof, a further right-angle bend normal to andextending toward said web, and a remaining right-angle bend in the planeof said web extending toward its said horizontal center line, the edgeof said remaining right-angle bend being welded to the first such bend,and closures for the respective ends of said flanges formed by saidbends, whereby a support member is provided having a section modulusabout its vertical neutral axis sufficient to withstand lateral bendingwhile at the same time said flanges may I be used as respective coolingpassages.

4. An elongated skewback member subjected to intense heat in open-hearthfurnaces or the like, said member having a vertical web adapted to bearat spaced horizontal intervals against vertical framework members ofsaid furnaces or the like, box section flanges formed integrally alongthe horizontal top and bottom edges of said member, each of said flangesbeing formed from the same plate material forming said web, said flangecomprising a right-angle bend inwardly of said web and normal thereto, afurther right-angle bend parallel to said web extending toward thehorizontal center line thereof, and a remaining right-angle bend normalto and extending to said web, the edge of said remaining right-anglebend being welded to said web, and closures for the respective ends ofsaid flanges formed by said bends, whereby a skewback memher is providedhaving a section modulus about its vertical neutral axis sufficient towithstand lateral bending while at the same time said flanges may beused as respective cooling passages.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2 742,549 Zeh et al Oct. 27, 1903 799,320 Franks Sept. 12,1905 1,267,057 Clarke May 21, 1918 1,371,906 Knox Mar. 15, 19211,915,398 Bedell et a1 June 27, 1933 2,294,946 Aldrich Sept. 8, 19422,321,074 Fon Dersmith et a1. June 8, 1943 2,521,325 Barnes Sept. 5,1950

